It is known to fabricate articles including a bundle of polymer optical fibers, for example, as disclosed in U.S. Pat. No. 4,923,268 to Xu. In the '268 patent there is shown and claimed a passive star coupler formed by placing a bundle of polymer optical fibers within a sleeve of shrink tube and melt-fusing the bundle so that an optical signal incident on one or more fibers in the bundle is distributed to all the fibers therein. The shrink tube employed by Xu is made of Teflon.RTM. fluoropolymer having a softening point approximating that of the fibers being melt-fused. Star coupler fabrication by this method involves removing the cladding layer of a polymer optical fiber which leads to undesirable optical signal attenuation.
It is typically desirable to include in illumination and display applications a light conducting element of about 1/2 a centimeter (1/4") or more in diameter. Monolithic devices are typically employed; however, such elements tend to be rigid and accordingly unsuitable for uses where flexibility is needed. Unlike optical star coupling applications, signal mixing is not required in illumination bundles and indeed, removal of cladding is to be avoided in order to reduce optical losses.